Radnor Lake State Park

It's hard to imagine that this beautiful lake is artificial, but so it is, built by a railway company in 1914 and handed over to public use in 1973. These days thousands of people visit every year (parking is limited, so arrive early on weekends), enjoying 6 miles of trails around the lake and in the surrounding woods. Look out for turtles, beavers, deer and otters, and take time to visit the bird center. Pets are not allowed on the trails.